A scary injury to pitcher Hiroki Kuroda put a tough loss in perspective for the Los Angeles Dodgers.

Los Angeles was leading by three when Kuroda was hit in the head by a line drive in the sixth inning, and the stunned Dodgers watched the host Arizona Diamondbacks rally for a 4-3 victory in 10 innings.

Tests revealed Kuroda suffered a concussion but no fractures or internal bleeding. He remained in St. Joseph’s Hospital overnight for observation.

Pinch-hitter Rusty Ryal lined a 2-2 delivery off the right side of Kuroda’s head leading off the sixth.

The 34-year-old Kuroda crumpled to the mound, clutching his head, as the ball deflected into the seats behind first base, then back onto the field. Ryal was awarded a ground-rule double when play resumed.

Ryal stopped at first base, then returned to the Arizona dugout while Kuroda was being treated on the mound.

“You get that sick feeling in your stomach,” said Ryal, playing in his fifth major league game. “I was just scared.”

All eight Dodgers fielders stood on the mound as trainers tended to Kuroda, who was placed on a stretcher and loaded onto a cart.

“One of the first things he asked out there was if anybody caught the ball out there, if it was an out,” trainer Stan Conte said.

Kuroda raised both of his arms as the cart rolled off the field.

Washington Nationals president Stan Kasten acknowledged there is a “very real possibility” the team will not reach an agreement with No. 1 overall draft pick Stephen Strasburg despite offering him a record-breaking contract.

The Nationals face a deadline of midnight on Monday night to sign Strasburg, a right-handed pitcher from San Diego State whose fastball has been clocked at 102 mph.

He is represented by Scott Boras, who has the top three players in this year’s draft — all of whom were unsigned as of Saturday afternoon.

Texas’ Ian Kinsler also was hit, but by a thrown pitch. He stayed in the game after he was hit in the helmet on a pitch from Fernando Cabrera in the eighth inning of the Rangers’ 7-2 win over Boston.